The present invention relates to an electrical contact device that is part of an electric switching device able to allow or interrupt the passage of an electrical current and a low-voltage single-pole phase unit incorporating such an electrical contact device.
It belongs to the field of low-voltage cutoff devices, and in particular the field of improving the interruption of electrical current, in particular when electric arcs occur.
The invention is particularly applicable in the field of low-voltage multi-pole electrical cutoff apparatuses formed by assembling single-pole phase units, electrically connected to a triggering unit that may comprise magnetothermal or electronic means.
Various models of such modular electrical cutoff apparatuses exist.
One such electrical cutoff apparatus is for example described in patent application FR2986659. This electrical cutoff apparatus comprises at least one single-pole phase unit, and preferably three single-pole phase units, each single-pole phase unit being connected to a triggering unit at a downstream connecting area. Each single-pole cutoff unit also comprises an upstream connecting area, making it possible to connect it to a current line.
Such a single-pole phase unit comprises a housing containing a moving contact bridge comprising a contact surface at each end, a pair of fixed contacts, each fixed contact cooperating with the moving contact bridge, and being connected to an electric current intake conductor. The contact surfaces of the moving contact bridge are respectively arranged on contact pads.
The contact pads play an important role, because they must provide good electrical contact in normal operation under rated current, while being robust with respect to wear.
Document DE4204641 describes a contact having a spherical-type contact surface, so as to monitor the position of the point of contact with an electrical contact, which makes it possible to achieve contact with good mechanical and electrical performance.
However, such a contact pad does not have sufficient performance regarding the elimination of any electric arc that may occur during opening of the contact.